1. Field of the Invention
The present invention relates to a sunroof device for vehicle in which a guide rail is disposed along a roof opening of a vehicle, rods to be pushed and pulled and guide members attached to said rods are placed within said guide rail, and said guide members are dynamically coupled with a drive mechanism for driving a lid to open and close the roof opening.
2. Description of the Related Art
A conventional sunroof device of this type is illustrated in FIG. 11. As shown, a guide rail 1 is usually disposed along the rear end of an opening formed in the roof of a vehicle. A cable 2 is inserted into the guide rail 1. The cable is pushed and pulled by a cable drive source, e.g., a motor.
Guide members 3, which are slidably inserted into the guide rail 1, are attached to the cable 2. A support portion 4 of each guide member 3 is protruded from and above an opening groove 1a of the guide rail 1 when the guide member 3 is inserted into the guide rail 1. The support portion 4 supports a link (not shown) of a drive mechanism for driving the lid to open and close the roof opening.
The cable 2 is capable of highly efficiently transmitting a load in a pulling direction. When it is moved in a pushing direction, a relatively large load acts on the cable as the result of, for example, frictional resistance of the guide member 3, and the cable is bent and buckled. For this reason, in the cable movement in the pushing direction, the power transmission efficiency is extremely reduced and hence, a large motor torque is required. If the motor torque is increased, sometimes the motor fails to satisfactorily move the cable.
Recently, to cope with this problem, there is a proposal to use the rods, in place of the cable 2, for the linear portion or a large R portion of the guide rail 1.
In this proposal using the rods in place of the cable, the rod diameter may be increased to lessen a chance of buckling of the rod. However, the increase of the rod diameter creates another problem to secure an unsatisfactory clearance between the rod and the inner wall of the guide rail since the space within the guide rail 1 is limited in the diametrieal direction of the rod When the diameter of the rods is large in the proposed sunroof structure, when the rod is buckled, it strongly hits the inner wall of the guide rail 1, to generate offensive or harsh sound. When the rod diameter is small, the rod is liable to be buckled, the power transmission efficiency is reduced, and the sunroof device operation fails, as in the case of using only the cable.